1. Field of the Invention
The present invention relates to a bumper assembly for a motor vehicle, and more particularly to a bumper beam having multiple material properties.
2. Description of the Related Art
Automotive designers are continually trying to balance the need for lightweight, fuel efficient automobiles with safety standards and regulations imposed by the government and insurance companies. One such automotive component subject to heavy regulation is bumper assemblies with regard to crash safety standards. The bumper assembly is traditionally comprised of a bumper beam made of a metallic material with the requisite strength to conform to governmental standards for low and high speed crashes. Often, the strong metallic beam is heavy and adds significant weight to the vehicle thereby reducing fuel efficiency. There is a need in the automotive industry to develop a bumper assembly having a bumper beam with an increased strength to weight ratio by lowering the overall weight of the bumper assembly. The improved bumper assembly must still be strong enough to provide excellent performance in high speed and low speed crashes.
Furthermore, automotive manufacturers desire components that are affordable and easy to produce in a mass production operation. Traditional bumper assemblies are roll-formed whereby a flat steel strip extends through a series of rollers to shape the steel into a desired form. Complex bumper beam designs, while providing the necessary strength to conform to safety standards, add to the time and cost of the manufacturing process. There is a need in the automotive industry to produce a bumper beam that provides strength adequate to conform to safety standards, lightweight to improve fuel efficiency and simple to manufacture.